Spawns generally need a few ways out, but not many in. Things like fairly high windows (high enough so spawnkillers can't climb up, but not too high as to hurt people coming out), and ramps/boards leaning against fences are all things that make spawns a little more fair in BC.

Jumping on top of lights like that is an easy way to get kills (and works), but is considered cheap by most. In most CS map guides, they warn you about where you can jump on top of exit signs. In my map, I'm currently building a noclip brush shaped like a wedge on top of exit signs and molding around buildings, so anyone who jumps on top will simply slide off. Is this a good idea, or stupidly unrealistic?